Nowadays, transfer printing method has become a new technology for daily-use industrial decoration and printing process of fabric. This technology generally includes the following steps: firstly, printing the desired a pattern or letter on a base paper by printing using a proper printing ink to produce a transfer printing paper; then, pressing the surface with the printing ink of the transfer printing paper to a blank fabric; and removing and peeling the printing ink from the transfer printing paper under the action of pressure and wetting, thereby transferring the a pattern or letter from the transfer printing paper to the fabric. Usually, the transfer printing method may be classified into thermal transfer printing method (i.e., hot-melt pressure sensitive transfer printing by heating) and cold transfer printing method (transfer printing at environmental temperature after padding with a pretreatment agent, no heat is needed).
Patent SU937468A1 in 1982 discloses a thickener for fabric printing, and patent SU1018409A1 in 1995 discloses a method for preparing an emulsion from methacrylic acid and butyl acrylate under the initiation of DMF in a solvent. The thickener and the resulting emulsion in the above two patents are different from the present invention not only in their preparation method, but also mainly in that they don't have the hydrotropic rate and peeling rate necessary for transfer printing, and thus can only be used as ordinary printing paste.
Patent JP50053687A in 1975 and patent U.S. Pat. No. 6,858,255B2 in 2005 also respectively relate to a printing paste, which is only used for fibril sizing and coat printing. Since the pastes don't have the technical standard necessary for transfer printing too, the catalyst system, solvent and additive used in the polymerization are different from those in the present invention, and the preparation steps are completely different from those in the present invention.
The most difficulty in transfer printing is that the printing ink can't be totally transferred from the printing paper to the fabric, a large amount of dyes remain on the printing paper, which causes a number of problems, including, for example, on one hand, the waste of a large amount of dyes, environmental pollution, and low regeneration rate of wastepaper, and on the other hand, low dye yield in transfer printing and poor color fastness of the printed fabric. Moreover, conventional transfer printing paper and transfer printing process thereof can be only used for chemical fabrics, especially polyester fabrics, but is not useful for natural fibers such as cotton, wool, silk and cellulose fiber etc., the reason is that natural fibers usually use water-soluble dyes, for example, reactive dyes or weak acidic dyes (cf. Dyeing & Finishing, 1999, No. 3, Wet Transfer Printing of Pure Cotton Fabric with Reactive Dyes), this water-soluble dyes will bond to paper so that it is difficult to transfer the a pattern or letter from the printing paper to the fabric, with a transfer rate of about 60% only. Therefore, there needs a connecting material between base paper and printing ink in a transfer printing paper, which can serve as not only an ink-receiving layer in printing but also an isolating layer in transfer printing, that is, the connecting material can make printing ink stay on the paper well and thus keep a high pattern sharpness, and at the same time can easily transfer the a pattern or letter printed with printing ink from the printing paper to the fabric, with a transfer rate of above 90%, as a result, the environmental pollution caused by ink residue is decreased, and the regeneration and utilization of wastepaper is increased.